I have heard rumors of a annual passholder preview event to be held next week possibly after park hours. I don't know how valid those are, but I sure hope that they are true. I really hope that Universal doesn't mess this up again like they did for Rip Ride Rockit where there was not a single annual passholder event. At least not to my knowledge. In fact there used to be passholder events throughout the year at Universal, but in the past two, three years I have seen nothing. Nothing since Kong closed and the Revenge of the Mummy ride opened.
If you are looking for Potter merchandise without having to go to the park, the Universal Orlando store at Orlando International Airport (MCO) has already begun to sell Potter gear that you will find in Hogsmeade stores.